diynetwork.com: How to Add Acid Stain to a Concrete Floor - Applying acid stain to a concrete floor can add dramatic marbling and give a depth of color not available in any other type of floor. These step-by-step instructions show DIYers how to obtain great results.
The Romans used methods to make it stable. There’s a supportive ring around the outside of the dome, arches made within the dome, and the concrete is cutout in patterns that seem to be decorative, but also serve to lighten it a great deal. Upon this, the Romans had created several types of concrete, concrete that can rival or in certain conditions surpass modern concrete.